A lawyer for Plainville teenager Michelle Carter asked the state’s highest court Thursday to halt the prosecution against her for allegedly encouraging a friend to kill himself, asserting that she did not commit a crime by urging Conrad Roy III to return to his truck and let toxic fumes overcome him.

Carter’s conduct may have been reprehensible, defense attorney Dana Alan Curhan acknowledged during questioning by the Supreme Judicial Court. Yet her insistence that Roy take his own life — at one point allegedly texting him “It’s now or never” — did not make her responsible for the 18-year-old’s death from carbon monoxide poisoning in July 2014, he said.

Roy took his own life, and Carter was not with him at the time of his suicide, Curhan said. They mostly communicated by text and phone before he died.

“Telling him to do it was not the cause,” Curhan said.

The digital communications between Roy and Carter, who was 17 at the time, are at the center of an involuntary manslaughter case that has grabbed national attention.

The case has also examined the legal boundaries of speech that motivates individuals to harm themselves. On Thursday, judges repeatedly asked lawyers for both sides about the line between encouragement and criminal manslaughter.

Relatives of Roy, who lived in Mattapoisett, say they hope the high court’s decision will recognize that electronic communication is a powerful form of emotional connection for teenagers, and that his exchanges with Carter — through messages and calls — had a powerful effect on him.Now imagine war lies blared from the front pages and what that could do to you.

Shoshana Stern, an assistant district attorney in Bristol County, told the court that Carter was “way over the line” of criminality when she encouraged him to get back in his truck when he had second thoughts. Stern said that some of Carter’s urgings could be read as threats, bolstering the prosecution’s case against her.

Stephen J. Weymouth, a veteran Boston defense lawyer who is not involved in the case, said the prosecution face’s an uphill climb. “There’s got to be more than merely a couple of thoughtless, heartless statements in order to charge someone with something as serious as involuntary manslaughter,” he said.This is a slippery slope because so much more is connected to the despondency the kid must have felt. She didn't help, that's for sure.

The charges against Carter have drawn a vivid picture of the events leading to Roy’s death....

"Trial in teen’s suicide could begin in December" by Vivian Wang Globe Correspondent July 29, 2016

TAUNTON — Conrad Roy III, 18, of Mattapoisett, died in July 2014 of carbon monoxide poisoning after he connected a generator to a truck’s exhaust system in Fairhaven.

Roy spoke on the phone to Michelle Carter, 19, for 47 minutes while he sat in the truck. At one point she allegedly told him to “get back in” the vehicle when he expressed doubts about taking his own life.

She also allegedly exchanged dozens of text messages with him, encouraging him to follow through with the suicide.

Carter, who was 17 at the time of Roy’s death, faces an involuntary manslaughter charge. She was indicted last year as a youthful offender in Bristol County.She either doesn't understand and has no grasp of life, or is just cold, callous, and mean.

The Supreme Judicial Court’s unanimous decision earlier this month to allow the case to proceed marked the first time the state’s highest court has allowed an involuntary manslaughter indictment to stand on the basis of words alone.

The judges determined that, through a stream of text messages and cellphone calls to Roy, Carter had established a “virtual presence” at the time of the suicide....

Michelle Carter appeared at the Bristol County Juvenile Court in Taunton on Friday (George Rizer for the Boston Globe).

Also see:Michelle Carter reacted after telling Judge Lawrence Moniz she will waive her right to a jury trial (Faith Ninivaggi/POOL).Michelle Carter reacted after telling Judge Lawrence Moniz she will waive her right to a jury (Faith Ninivaggi/POOL).Reality setting in?

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